I can't speak for most pax, but whether I do depends on things like the flight time and meals served. On 830, for example, they serve a main meal right after takeoff, but it's not breakfast. At that hour, I need breakfast, so I have a regular breakfast in The Wing first, then eat when I'm hungry, 7+ hours into the flight. When there are opup pax in F, the FAs always ask for my preference when they're taking orders for the meal so that they will save what I want in case there weren't enough of my choice loaded.